Summing over topologies in non‑perturbative gravitational path integrals
Establish a mathematically controlled prescription for the sum over spacetime topologies in the non‑perturbative gravitational path integral by overcoming the super‑exponential growth of configurations and defining a unique, well‑posed procedure.
References
In particular, Loll stated that in the non-perturbative gravitational path integral, no one knows how to make sense of summing over topologies because of the super-exponential growth of configurations, which not even in two dimensions can be controlled uniquely.
                — Visions in Quantum Gravity
                
                (2412.08696 - Buoninfante et al., 11 Dec 2024) in Panel 2 (Subsection "Unitarity, causality, stability")